In food processing industries where grease, protein, starch, etc. build up into layers of varying thickness and soil the surfaces of equipment, processes must be periodically shut down for equipment cleaning. Various formulations and methods have been used in an attempt to resolve this problem. Conventional formulations have included various surfactants with alkaline cleaning agents containing chlorine. Due to the presence of chlorine in the alkaline agent, the longer molecular structures of the protein, starch and grease components are cleaved into shorter molecular structures which are then capable of being emulsified by surfactants and flushed away.
One problem associated with such formulations is that the chlorine content of the cleaning solutions creates a negative environmental impact. Furthermore, chlorine accelerates the corrosion of metallic components, as well as the degradation of various rubber gaskets and seals. It is therefore desirable to formulate solutions for cleaning heavily soiled surfaces in the food processing industry which avoid the problems caused by using conventional chlorine-based formulations.
Various attempts have been made to achieve the desired result of cleaning these heavily soiled surfaces while not compounding environmental pollution. For example, U.S. Pat. No. 5,567,444 discloses the use of potentiated ozone as a cleaning agent. The ozone is generated by creating an electrical charge to contact a solution containing hydrogen peroxide and peroxyaliphatic carboxylic acid. Although ozone is known to have a relatively short lifetime after being generated, one of the disadvantages of using this molecule relates to its status as a possible environmental hazard since it is known to be a major contributor to the formation of smog in urban areas.
U.S. Pat. No. 5,855,217 discloses a device for cleaning soiled food processing equipment in which a hydrogen peroxide solution containing an alkyl amine oxide is added to a chlorine free alkaline foam cleaning agent no more than 1 minute prior to application to the soiled surface to be cleaned. The alkaline cleaning agent is foamed before being mixed with the hydrogen peroxide solution. The examples show a cleaning efficiency rate of only between 41.5% and 75.5%, which may be acceptable under some, although not all, industrial cleaning operational standards.
In U.S. Pat. No. 5,861,366, the patentees disclose the use of enzymes plus surfactants to clean soiled food processing equipment. They mention a number of conventional formulations that may be combined with these enzymes to augment the cleaning process. They emphasize that their formulation is free of chlorine and alkaline metal hydroxides. While enzymes may exhibit less negative environmental impact, they typically lack the cleaning efficiency required in many industrial operations with limited time constraints.
Another approach is provided by the disclosure of U.S. Pat. No. 6,686,324 B1. This patent teaches a low foaming cleaning solution for cleaning and disinfecting medical and dental equipment by removing light organic soiling. The cleaning solution also includes a variety of surfactants, polyphosphates, sequestering agents and corrosion inhibitors. It is not suggested that this formulation be used to clean the heavily soiled surfaces of food processing equipment.
U.S. Pat. No. 6,998,376 B1 discloses a method and formulations for cleaning equipment used to prepare coffee. The alkaline cleaning solution contains at least one peroxidic compound generating about 1.5% active oxygen. No mention is made of utility in the cleaning of heavily soiled surfaces of the equipment used in the food processing industry.
Recent U.S. Patent Publications 2006-0046945 and 2006-0042665 disclose a method for the cleaning in place of soiled industrial equipment. However, they merely disclose a multistep process using conventional cleaning chemicals. They appear to claim that a pre-treatment, which can be either acidic or caustic, improves cleaning efficiencies. It is not clear, though, how this is an advancement over the known art.
What is desired is a more efficient formulation and method for use with “clean out-of-place” (COP), “clean-in-place” (CIP) and foam cleaning operations to remove heavy soil from surfaces of the equipment used in the food processing industry. This and other objectives will become apparent from the following detailed description of the invention.